1. 本实例使用的RocketMq版本为4.3.2, JDK>=1.8
2. 启动rocketmq, 在安装目录的bin目录下
启动 NAMESERVER start mqnamesrv.cmd
启动 BROKER start mqbroker.cmd -n 127.0.0.1:9876 autoCreateTopicEnable=true
3. rocketmq jar包
<dependency> <groupId>org.apache.rocketmq</groupId> <artifactId>rocketmq-client</artifactId> <version>4.3.2</version> </dependency>
4. application.properties
# 消费者组名 apache.rocketmq.consumer.PushConsumer=PushConsumer2 # 生产者的组名 apache.rocketmq.producer.producerGroup=Producer4 # NameServer的地址 apache.rocketmq.namesrvAddr=127.0.0.1:9876
Topic 默认对应四个队列 queue, 队列中有生产者和消费者, 生产者组成生产者组, 消费者组成消费组
有相同名称的是属于同一个组的, 一个queue对应一个消费者, 但一个消费者对应多个queue
setConsumeMessageBatchMaxSize ---- 设置批量消费消息的大小 (1: 一次一条 n: 一条多条)
消息消费完成后, 如果消费者返回CONSUME_SUCCESS则消息成功被消费
如果消费者返回RECONSUME_LATER 则消息在一段时间后会被再次消费
produce0 -------> queue0 --------> consume0
ProduceGroup produce1 -------> queue1 --------> consume1 ConsumeGroup
produce2 -------> queue2 --------> consume2
produce3 -------> queue3 --------> consume3
5. 事务生产者代码
@Component public class TransactionProducer { @Value("${apache.rocketmq.producer.producerGroup}") private String producerGroup; @Value("${apache.rocketmq.namesrvAddr}") private String namesrvAddr; public void transactionProduce() throws MQClientException, InterruptedException { TransactionListener transactionListener = new TransactionListenerImpl(); TransactionMQProducer producer = new TransactionMQProducer(producerGroup); producer.setNamesrvAddr(namesrvAddr); ExecutorService executorService = new ThreadPoolExecutor(2, 5, 100, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(2000), new ThreadFactory() { @Override public Thread newThread(Runnable r) { Thread thread = new Thread(r); thread.setName("client-transaction-msg-check-thread"); return thread; } }); producer.setExecutorService(executorService); producer.setTransactionListener(transactionListener); producer.start(); String[] tags = new String[] {"TagA", "TagB", "TagC", "TagD", "TagE"}; for (int i = 1; i <= 2; i++) { try { Message msg = new Message("TopicTest1234", "transaction"+i, "KEY" + i, ("Hello RocketMQ " + i).getBytes(RemotingHelper.DEFAULT_CHARSET)); SendResult sendResult = producer.sendMessageInTransaction(msg, Integer.parseInt("1")); System.out.printf("%s%n", sendResult); Thread.sleep(10); } catch (MQClientException | UnsupportedEncodingException e) { e.printStackTrace(); } } /*for (int i = 0; i < 100000; i++) { Thread.sleep(1000); }*/ producer.shutdown(); } }
6. 消息事务回调提交
public class TransactionListenerImpl implements TransactionListener { private AtomicInteger transactionIndex = new AtomicInteger(0); private ConcurrentHashMap<String, Integer> localTrans = new ConcurrentHashMap<>(); @Override public LocalTransactionState executeLocalTransaction(Message msg, Object arg) { System.out.println("执行本地事务msg = " + new String(msg.getBody())); System.out.println("执行本地事务arg = " + arg); String tags = msg.getTags(); if (tags.equals("transaction2")) { System.out.println("======我的操作============,失败了 -进行ROLLBACK"); return LocalTransactionState.ROLLBACK_MESSAGE; } return LocalTransactionState.COMMIT_MESSAGE; // return LocalTransactionState.UNKNOW } @Override public LocalTransactionState checkLocalTransaction(MessageExt msg) { Integer status = localTrans.get(msg.getTransactionId()); if (null != status) { switch (status) { case 0: return LocalTransactionState.UNKNOW; case 1: return LocalTransactionState.COMMIT_MESSAGE; case 2: return LocalTransactionState.ROLLBACK_MESSAGE; } } return LocalTransactionState.COMMIT_MESSAGE; } }
7. 消费者代码
@Component public class RocketMQConsumer { @Value("${apache.rocketmq.consumer.PushConsumer}") private String consumerGroup; @Value("${apache.rocketmq.namesrvAddr}") private String namesrvAddr; @PostConstruct public void defaultMQPushConsumer() { DefaultMQPushConsumer consumer = new DefaultMQPushConsumer(consumerGroup); //设置最多一次消费多少条 consumer.setConsumeMessageBatchMaxSize(1); consumer.setNamesrvAddr(namesrvAddr); // consumer.setMessageModel(MessageModel.CLUSTERING); try { consumer.subscribe("TopicTestA", "push"); consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET); consumer.registerMessageListener((MessageListenerConcurrently) (list, context) -> { try { for (MessageExt messageExt : list) { System.out.println("messageExt: " + messageExt);// 输出消息内容 String messageBody = new String(messageExt.getBody(), RemotingHelper.DEFAULT_CHARSET); /*System.out.println("----消费响应:msgId : " + messageExt.getMsgId() + ", msgBody : " + messageBody + " " + Thread.currentThread().getName());*/ int reconsumeTimes = messageExt.getReconsumeTimes(); //消费次数为2时,将消息消费掉 if(reconsumeTimes >= 2){ System.out.println("----消费响应:msgId : " + messageExt.getMsgId() + ", msgBody : " + messageBody + " " + Thread.currentThread().getName() + " 消费次数:" + reconsumeTimes); return ConsumeConcurrentlyStatus.CONSUME_SUCCESS; }else{ System.out.println("++++消费响应:msgId : " + messageExt.getMsgId() + ", msgBody : " + messageBody + " " + Thread.currentThread().getName() + " 消费次数:" + reconsumeTimes); return ConsumeConcurrentlyStatus.RECONSUME_LATER; } } } catch (Exception e) { e.printStackTrace(); return ConsumeConcurrentlyStatus.RECONSUME_LATER; // 稍后再试 } return ConsumeConcurrentlyStatus.CONSUME_SUCCESS; // 消费成功 }); consumer.start(); } catch (MQClientException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }